8bc4

Publication Abstract from PubMed

Sulfoquinovose (SQ) is a key component of plant sulfolipids (sulfoquinovosyl diacylglycerols) and a major environmental reservoir of biological sulfur. Breakdown of SQ is achieved by bacteria through the pathways of sulfoglycolysis. The sulfoglycolytic sulfofructose transaldolase (sulfo-SFT) pathway is used by gut-resident firmicutes and soil saprophytes. After isomerization of SQ to sulfofructose (SF), the namesake enzyme catalyzes the transaldol reaction of SF transferring dihydroxyacetone to 3C/4C acceptors to give sulfolactaldehyde and fructose-6-phosphate or sedoheptulose-7-phosphate. We report the 3D cryo-EM structure of SF transaldolase from Bacillus megaterium in apo and ligand bound forms, revealing a decameric structure formed from two pentameric rings of the protomer. We demonstrate a covalent "Schiff base" intermediate formed by reaction of SF with Lys89 within a conserved Asp-Lys-Glu catalytic triad and defined by an Arg-Trp-Arg sulfonate recognition triad. The structural characterization of the signature enzyme of the sulfo-SFT pathway provides key insights into molecular recognition of the sulfonate group of sulfosugars.

Structure and mechanism of sulfofructose transaldolase, a key enzyme in sulfoquinovose metabolism.,Snow AJD, Sharma M, Abayakoon P, Williams SJ, Blaza JN, Davies GJ Structure. 2023 Mar 2;31(3):244-252.e4. doi: 10.1016/j.str.2023.01.010. Epub 2023 , Feb 17. PMID:36805128^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.